Central Bureau for Astronomical Telegrams
IAUC 3597: CRAB PULSAR; R Crt; 1980b; ASTROGRAM CAM /= Sat CAM
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Read IAUC 3598
Circular No. 3597
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
CRAB PULSAR
R. Murthy reports: "We have collected data on event times of
ultra-high-energy gamma-rays and protons in the direction of the Crab
pulsar. We used the atmospheric Cerenkov technique with the aim of
detecting pulsed high-energy gamma-rays. Since the background is large
and the signal expected to be weak, the data need to be folded over
and the pulsar phase carried through over three months using accurate
information on the Crab pulsar period and its first and
second time derivatives. Our data cover 1981 Jan.-Mar. We are
soliciting relevant information from any group that may have observed
the Crab pulsar in any wavelength window since 1980 Oct. We
can be contacted at the address: Tata Institute of Fundamental Research,
Colaba, Bombay 5, India."
R CRATERIS
S. H. B. Livi and T. S. Bergmann, Instituto de Fisica, UFRGS,
using the 0.50-m telescope at Morro Santana, Porto Alegre, Brazil,
detected variations in the SRb variable R Crt with ~ 40 min between
peaks on Feb. 24. The DDO photometric system was used. The amplitudes
were 0.2 mag in C(42-45) and C(45-48), 0.1 mag in C(41-42),
0.07 in B-V and < 0.05 in V. The main variations are in the 42 and
45 filters, which vary in a reverse way. Similar variations were
previously detected in radio on the 22-GHz H2O line by A. Gomez
Balboa, J. R. D. Lepine and N. Pires at the Observatono Nacional,
Brazil.
COMET BOWELL (1980b)
Though relatively bright, this unique comet has been largely
ignored at this opposition. Recent total visual magnitude estimates
are: Apr. 7.07 UT, 11.6 (J. Bortle, Stormville, NY, 0.32-m
reflector); 8.86, 11.8 (J.-C. Merlin, Le Creusot, France, 0.26-m
reflector); 11.20, 11.8 (C. S. Morris, Harvard, MA, 0.25-m reflector).
A current ephemeris is on MPC 5419. Improved orbital elements
are given on MPC 5897.
ASTROGRAM CAM /= SATELLITE CAM
Contributors are requested to use the TWX number 710-320-6842,
not the Smithsonian's telex number, when communicating information.
1981 April 23 (3597) Brian G. Marsden
Read IAUC 3598
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